Cheques are known in the art.
Also known in the art is the Magnetic Ink Character Recognition (MICR) technology used mainly by the banking industry to ease the processing and clearance of cheques and other documents.
As is known, according to the MICR technology, magnetic characters printed on documents, in a first step are magnetically charged by means of a magnetic field and in a second step their magnetic signals are read according to the respective reading standards.
According to the known art the second step, to which the present invention relates, is made by using a device 1 (FIG. 1) comprising a reading head 2, an amplifier 5, an A/D converter 6, and a control unit (CPU) 8.
The known device is arranged to:
read the signals of the magnetic characters by means of the reading head 2;
amplify the signals by means of the amplifier 5;
sample and convert the signals into a plurality of data by means of the A/D converter 6; and
process the plurality of data by means of the CPU 8 so as to reproduce the read characters and, for instance, send them to other processing devices, per se known to the skilled person and hence not described here.
An apparatus of this type is known, for instance, from publication WO2006/005560 in the name of the Applicant that is arranged for reading, decoding and certifying documents comprising magnetic characters or patterns.
Reading of the magnetic characters, however, is adversely affected by a plurality of problems, such as, for instance:
very low magnetic field of the characters;
electromagnetic noise due to electromagnetic frequencies generated by stepping motors that are typically present in the reading devices;
electromagnetic noise due to electromagnetic frequencies generated by switching transformers that are typically present in or near the reading devices;
electromagnetic noise due to electromagnetic frequencies coming, in general, from external sources.
In summary, the magnetic low level signal of the characters and the electromagnetic noise due to a plurality of sources render it very difficult, if not impossible in certain situations, to correctly read and decode the magnetic characters.
As a matter of fact, the noise-generating electromagnetic frequencies read by the head have typically the same magnitude as the signals to be amplified.
In general, the Applicant has found that known devices, intended for implementing a reliable process of reading magnetic characters, are very complex, due, for instance, to the installation of shields on the noise-generating devices or on the head so as to indirectly or directly protect with shields the process of reading magnetic characters.
In the above cases, shielding is made by means of metal sheets located near the sources of the electromagnetic noise or near the head so as protect the head from the electromagnetic frequencies.
However, the above shields have high intrinsic and manufacturing costs.